The mediators were gathering in Tigray's capital Mekele, Nuur Mohamud Sheekh, spokesperson for the regional Intergovernmental Authority on Development (IGAD), said on Thursday.
Getachew Reda, spokesperson for the regional Tigray People's Liberation Front (TPLF), and Ethiopian national security advisor Redwan Hussien did not respond to requests for comment.
Under the peace deal, the monitoring team was supposed to be in place by Nov. 22. Tigrayan leaders complained about delays establishing it and implementing other provisions of the truce.
The Nov. 2 ceasefire quieted a two-year conflict that killed tens of thousands and displaced millions in the Horn of Africa country, but implementation of parts of the deal has been slower than hoped.
Humanitarian workers in Tigray say troops from neighbouring Eritrea - which should have withdrawn under the terms of the truce - are still present in several towns there, a region where millions remain hungry and needing aid.
Eritrea's government has not commented.
Both the issue of Eritrean forces and the restoration of services and humanitarian aid to Tigray were expected to be in the agenda of a monitoring team being set up by the mediators.